Abstract

Optical reflectivity has been measured in the far infrared (FIR) region on the blue bronze K0.3MoO3 system using polarized light. At room temperature the reflectance spectrum polarized (P) parallel to the b-axis is metal-like while the perpendicular spectrum is semiconductor-like. For T<Tc = 180 K the P∥b spectrum becomes also semiconductor-like with a very strong polarization dependent phonon spectrum. At hω < 8 meV a giant structure dominates the whole P∥b spectrum. The structure, reaching reflectivity values of 97% and having a width of 7 meV, is assigned to the phase oscillations of the pinned CDW. Optical constants are calculated by means of the Kramers Kronig relation. An LCAO calculation has been performed for one chain of K0.3MoO3: the results E(k), EF, kF, D(EF) m*e are compared with the experimental data.